


Demons of the Past

by TheFoolsKnight



Series: Lbotw Countdown Event [9]
Category: The Eldest Curses Series - Cassandra Clare, The Mortal Instruments Series - Cassandra Clare, The Shadowhunter Chronicles - Cassandra Clare
Genre: Battle, Book 1: The Red Scrolls of Magic, Demons, Gen, How Do I Tag, Kissing, M/M, Magic, Trauma
Language: English
Status: Completed
Published: 2020-08-30
Updated: 2020-08-30
Packaged: 2021-03-06 23:27:17
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,616
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26197111
Author URL: https://archiveofourown.org/users/TheFoolsKnight/pseuds/TheFoolsKnight
Summary: What starts out as an ordinary working day for Alec and Magnus quickly takes a dark turn when Alec stumbles upon a familiar demon during his patrol.
Relationships: Magnus Bane/Alec Lightwood
Series: Lbotw Countdown Event [9]
Series URL: https://archiveofourown.org/series/1890874
Comments: 6
Kudos: 68





	Demons of the Past

“Are you sure this is the right place?” Alec asked as they crept through the sewers.

“I’m absolutely sure,” Jace said, leading them with a sensor in his hand. Alec was holding the rear, his bow held firm in his hand as he and Jace, along with Clary and Isabelle walked through the old subway tunnels. They had been patrolling aboveground when their sensors had picked up high demonic activity. There was nothing in any of the buildings nearby, which meant the demonic activity was underground, and ‘underground’ just so happened to be the sewers.

“It stinks down here,” Isabelle grumbled, casting a dark glance at the murky sewer water.

“Well it’s sewage,” Jace said. “It’s hardly going to smell pleasant.”

Isabelle frowned. “I’m supposed to go visit Simon at the Academy tomorrow. How am I supposed to do that if I end up smelling like a dump?”

“Don’t worry, I’m sure it will be fine,” Clary said, a bright witchlight held in her hand.

Isabelle was about to say something else when Jace hissed at them to be silent. He held up the sensor, and Alec nerves were instantly alert when the quiet hum of the vibrating sensor reached his ears.

“It’s just around the corner,” Jace whispered, pointing to a turn in the sewer. He peeked around the corner and made a beckoning gesture, a signal that they should follow him.

Alec nocked an arrow in his bow, and waited until Jace rounded the corner, swiftly followed by Isabelle and Clary. There was a loud howling sound and a thwack, and Alec turned, aiming and letting an arrow loose.

He could see Jace and Isabelle and Clary’s blurred forms as they battled with the demon, heard the whoosh of the arrow, and a thump as it hit the target. But the demon seemed to be unaffected, and Alec heard another thrashing sound and a grunt from Jace. The witchlight Clary was holding had gone dim, and all Alec could see was a dark roiling shape, with what looked like swirls of smoke around it. He cursed and quickly drew a night vision rune on his arm.

The darkness of the sewer cleared somewhat, and Alec’s jaw dropped when he saw the demon more clearly. It was much larger than he initially thought, and what he assumed to be smoke were actually tentacles, each one as large as a tree trunk.

He watched as one of the tentacles grabbed Isabelle, hauling her off her feet, but his eyes were seeing a different scene entirely - the rooftop of a train, late at night, a horde of demons after Magnus.

“By the Angel,” he whispered mostly to himself. Almost by reflex, he fired an arrow at the tentacle that was holding Isabelle. “Not this thing again.”

Isabelle freed her arm and lashed out with her whip, landing a hit on the tentacle. The demon let go of her and she dropped, landing neatly on the ledge beside the sewage.

“You know what this thing is?!” Jace yelled at Alec, grappling with two of the tentacles at once.

“I do!” Alec fired three arrows in rapid succession, and then quickly reached for his phone. “And I know exactly how to stop it!”

Magnus had just finished his work and was preparing a drink for himself when his phone rang. He grinned when he saw the caller ID, and immediately picked it up.

A pleasant night, a glass of wine and his love on the phone. Things were going extremely well right now.

“Hey, babe!” he greeted, putting the bottle of wine aside and picking up the glass with a flourish. “I was just thinking of you-“

“Magnus, I need you!” Alec shrieked.

Magnus blinked, and then a slow, sly smile spread across his face. “Well, if you say so. I’ll get the rope ready by the time you get here.”

It looked to him like the night was getting much, much better.

“What?!” Alec sounded like he was very confused. “No!”

“No rope then?” Magnus enquired. “How about handcuffs?”

Alec let out a sound, which, Magnus supposed, was to be written on paper, would look something like ‘afjshdjdksk’. “ _ No _ ! None of that! There’s a raum brood mother in the sewers near Central Park. You need to get here ASAP!”

“A Raum Brood mother?” For some reason, a chill spread throughout Magnus’s body. He didn’t know why, but he had a very bad feeling about this demon, though he couldn’t recollect exactly what it was. There were too many types of demons.

“The octopus monster!” Alec clarified. “The one we fought on the train!”

_ Oh. _

Magnus’s hand jerked, and a bit of wine splashed out of the glass and landed on the carpet below. But wine stains were the last thing on Magnus’s mind right now. All he could see was a ravine stretching out below him, the red outline of a pentagram, and a large demon advancing towards him as Alec faded into unconsciousness in his arms.

“You need to get here!” Alec was saying right now on the phone. “And hurry! It’s-“

Magnus felt a pit open up in his stomach when there was a strange sound, like a scuffle and then a crash. A low howl sounded through the phone, chilling Magnus to the bone.

“Alec?” Magnus said in a low voice, but there was no reply.

It took Magnus five minutes to create a portal to Central Park, and five minutes more to find the sewers and hunt down Alec and company. It wasn’t hard - he could hear the sounds of fighting, echoing down the long sewer tubes.

_ Please be safe,  _ he was thinking over and over as he ran towards the howls of the demon.  _ Please be safe, Alexander, please, please, please- _

He couldn’t bring himself to think;  _ Please be alive. _

Magnus rounded one last corner and found the demon hovering tall over him, its large tentacles whipping around. Many a people thought that his warlock mark was just for show, but the cat eyes were functional, too - he could see  _ extremely well  _ in the dark.

He had planned to fire a sonic spell as soon as he saw the demon, but now he was rooted to the ground. He could hear the Shadowhunters shout as they battled the demon, could see quick flashes of seraph blades and the glint of metal. He couldn’t see Alec anywhere.

Thoughts of the night on the train rose up again in his mind. Try as much as he could, Magnus simply couldn’t shut them down. 

And  _ Alec.  _ Where was he? Had something happened to him? Was he-

The demon must’ve sensed him, because a tentacle shot out at him. Magnus was numb, and could only watch as the tentacle advanced towards him. He knew he ought to use his magic, but it was like his body had turned to ice. He felt cold and numb all over, and couldn’t move.

It was inches away from Magnus when a shape jumped in front of Magnus, blocking the tentacle. A seraph blade slashed through the air, and the demon retracted its tentacle with a howl, thick drops of ichor dropping onto the floor. The person turned, and in the light of the seraph blade Magnus could see his blue, blue eyes and fair skin, marred by a bleeding cut on his cheek.

“Hey,” Alec said, shooting him a tiny grin. “You’re here. Sorry if I scared you. I dropped my phone in the sewage.”

Magnus’s shoulders slumped, and he let loose a breath of relief. “Your face-“

Alec waved his concerns aside. “Later. You need to dispatch the demon first. Do you need my strength?”

“It’s fine,” Magnus said, taking a deep breath and moving his hands, slowly at first and then more rapidly as the spell began to take shape. “I can handle this.”

He could face anything, as long as Alec was safe.

There was no need to worry about the shadowhunters - the spell Magnus was casting was at a very high frequency, one that wouldn’t affect humans at all but could tear demons apart. He fired the spell at the brood mother, a thick ray of pure blue flame. It hit the demon right in the center and it howled, the sound loud enough to make the walls of the sewers tremble. The demon folded in one itself, and disappeared.

Alec let out a sigh of relief as soon as the demon disappeared. Magnus immediately grabbed him, kissing him on the mouth, his hands flitting about his body checking for any injuries and healing the cut on his cheek. Alec smiled into the kiss and had just leaned into Magnus when they heard Jace cough derisively from nearby.

The two parted and turned to Jace, who had his arms folded in front of him.

“So,” he said, raising an eyebrow. “How do you know this demon?”

“We fought one when we were on vacation,” Alec admitted. “It was tough, but there was another warlock to help us.”

“Wait,” Isabelle said with a frown. “Did that have anything to do with that whole cult business?”

“Cult business?” Clary echoed with a frown. “What are you talking about?”

“Sorry.” Isabelle bit her lip. “I forgot that was supposed to be a secret.”

“What secret?” Jace said incredulously. “What are you talking about?”

Alec looked at Magnus, and he didn’t need to speak for Magnus to understand him. It had to be his choice, whether he wanted these people to know about the Crimson Hand or not.

“It’s a long story,” Magnus said to them. “Let’s go to my loft and get you some iratzes, and then we’ll talk.”


End file.
